[PATCH 2/3] drm/uapi: add explicit virtgpu context debug name

[Gurchetan Singh]

There are two problems with the current method of determining the
virtio-gpu debug name.

1) TASK_COMM_LEN is defined to be 16 bytes only, and this is a
   Linux kernel idiom (see PR_SET_NAME + PR_GET_NAME). Though,
   Android/FreeBSD get around this via setprogname(..)/getprogname(..)
   in libc.

   On Android, names longer than 16 bytes are common.  For example,
   one often encounters a program like "com.android.systemui".

   The virtio-gpu spec allows the debug name to be up to 64 bytes, so
   ideally userspace should be able to set debug names up to 64 bytes.

2) The current implementation determines the debug name using whatever
   task initiated virtgpu.  This is could be a "RenderThread" of a
   larger program, when we actually want to propagate the debug name
   of the program.

To fix these issues, add a new CONTEXT_INIT param that allows userspace
to set the debug name when creating a context.

It takes a null-terminated C-string as the param value.

Link to open-source userspace:
https://android-review.googlesource.com/c/platform/hardware/google/gfxstream/+/2787176

Signed-off-by: Gurchetan Singh <gurchetansingh at chromium.org>
---
 include/uapi/drm/virtgpu_drm.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h
index b1d0e56565bc..c2ce71987e9b 100644
--- a/include/uapi/drm/virtgpu_drm.h
+++ b/include/uapi/drm/virtgpu_drm.h
@@ -97,6 +97,7 @@ struct drm_virtgpu_execbuffer {
 #define VIRTGPU_PARAM_CROSS_DEVICE 5 /* Cross virtio-device resource sharing  */
 #define VIRTGPU_PARAM_CONTEXT_INIT 6 /* DRM_VIRTGPU_CONTEXT_INIT */
 #define VIRTGPU_PARAM_SUPPORTED_CAPSET_IDs 7 /* Bitmask of supported capability set ids */
+#define VIRTGPU_PARAM_EXPLICIT_DEBUG_NAME 8 /* Ability to set debug name from userspace */
 
 struct drm_virtgpu_getparam {
 	__u64 param;
@@ -198,6 +199,7 @@ struct drm_virtgpu_resource_create_blob {
 #define VIRTGPU_CONTEXT_PARAM_CAPSET_ID       0x0001
 #define VIRTGPU_CONTEXT_PARAM_NUM_RINGS       0x0002
 #define VIRTGPU_CONTEXT_PARAM_POLL_RINGS_MASK 0x0003
+#define VIRTGPU_CONTEXT_PARAM_DEBUG_NAME      0x0004
 struct drm_virtgpu_context_set_param {
 	__u64 param;
 	__u64 value;
-- 
2.42.0.655.g421f12c284-goog